Aerosol separator and method

ABSTRACT

An arrangement for separating a hydrophobic liquid phase from a gaseous stream includes a coalescer filter, a housing, a gas flow direction arrangement, and a liquid collection arrangement. The coalescer filter includes a non-woven media of fibers. The housing includes an interior having a gas flow inlet and a gas flow outlet. The liquid collection arrangement is positioned within the housing construction and is oriented for receiving liquid collected from the coalescer filter and drained therefrom.

This application is a continuation-in-part of Ser. No. 09/474,616 filedDec. 29, 1999 now U.S. Pat. No. 6,290,739.

TECHNICAL FIELD

This disclosure relates to systems and methods for separatinghydrophobic fluids (such as oils) which are entrained as aerosols, fromgas streams (for example, air streams). Preferred arrangements alsoprovide for filtration of other fine contaminants, for example carbonmaterial, from the gas streams. Methods for conducting the separationsare also provided.

BACKGROUND

Certain gas streams, such as blow-by gases from the crankcase of dieselengines, carry substantial amounts of entrained oils therein, asaerosol. The majority of the oil droplets within the aerosol aregenerally within the size of 0.1-5.0 microns.

In addition, such gas streams also carry substantial amounts of finecontaminant, such as carbon contaminants. Such contaminants generallyhave an average particle size of about 0.5-3.0 microns.

In some systems, it is desirable to vent such gases to the atmosphere.In general, it is preferred that before the gases are vented to theatmosphere, they be cleaned of a substantial portion of the aerosoland/or organic particulate contaminants therein.

In other instances, it is desirable to direct the air or gas stream intoequipment. When such is the case, it may be desirable to separateaerosol and/or particulates from the stream during the circulation, inorder to provide such benefits as: reduced negative effects on thedownstream equipment; improved efficiency; recapture of otherwise lostoils; and/or to address environmental concerns.

A variety of efforts have been directed to the above types of concerns.The variables toward which improvements are desired generally concernthe following: (a) size/efficiency concerns; that is, a desire for goodefficiency of separation while at the same time avoidance of arequirement for a large separator system; (b) cost/efficiency; that is,a desire for good or high efficiency without the requirement ofsubstantially expensive systems; (c) versatility; that is, developmentof systems that can be adapted for a wide variety of applications anduses, without significant re-engineering; and, (d)cleanability/regeneratability; that is, development of systems which canbe readily cleaned (or regenerated) if such becomes desired, afterprolonged use.

SUMMARY OF THE DISCLOSURE

A filter arrangement is provided that includes a first stage coalescerfilter and a second stage filter element downstream from the coalescerfilter. Preferably, the first stage coalescer filter comprises anon-woven fibrous media. The second stage filter element will preferablyinclude pleated media. Preferred constructions will include a filterarrangement including a tubular extension of pleated media defining anopen filter interior; a first end cap at one end of the tubularextension of pleated media; the first end cap having an aperture incommunication with the open filter interior; a second end cap at an endof the tubular extension of media opposite of the first end cap; and thefibrous media oriented in flow communication with the open filterinterior.

In preferred embodiments, a flow construction arrangement is orientedwithin the open filter interior oriented to direct fluid from the regionof pleated media.

Preferably, a preformed insert comprising a frame construction holds thefibrous media, and is secured to the first end cap.

A gas cleaner is described that includes a housing construction withfilter arrangements, constructed according to principles herein,operably installed and removably replaceable within the housingconstruction.

In preferred applications, filter arrangements as described herein areusable to clean blowby gases from the crankcase of an engine. Systems,methods of use, and servicing are described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an engine system using a filterarrangement constructed according to principles of this disclosure;

FIG. 2 is a side elevational view of one embodiment of a filterarrangement, constructed according to principles of this disclosure;

FIG. 3 is an end view of the filter arrangement depicted in FIG. 2;

FIG. 4 is a cross-sectional view of the filter arrangement depicted inFIGS. 2 and 3, and taken along the line 4—4 of FIG. 3;

FIG. 5 is a cross-sectional view of one embodiment of a filter elementutilized in the filter arrangement of FIGS. 2-4; the cross-section beingthe same cross-section taken along the line 4—4, but depicting thefilter element removed from the housing construction;

FIG. 6 is a cross-sectional view of one embodiment of the housingconstruction body; the cross-section being analogous to thecross-section taken along the line 4—4, but depicting only the housingconstruction body and with a lid removed;

FIG. 7 is a cross-sectional view of one embodiment of the housingconstruction cover member; the cross-section being analogous to thecross-section taken along the line 4—4, but depicting only the housingconstruction cover member;

FIG. 8 is a cross-sectional view of a first alternative embodiment of afilter element that can be utilized in the filter arrangement of FIGS.2-4; the cross-section being analogous to the cross-section of FIG. 5;

FIG. 9 is a cross-sectional view of a second alternative embodiment of afilter element that can be utilized in the filter arrangement of FIGS.2-4; the cross-section being analogous to the cross-section of FIG. 5;

FIG. 10 is a perspective view of another embodiment of a filterarrangement, constructed according to principles of this disclosure;

FIG. 11 is a top plan view of the filter arrangement depicted in FIG.10;

FIG. 12 is a cross-sectional view of the filter arrangement depicted inFIGS. 10 and 11, and taken along the line 12—12 of FIG. 11;

FIG. 13 is an end view of one embodiment of a filter element utilized inthe filter arrangement of FIGS. 10-12;

FIG. 14 is an opposite end view of the filter element depicted in FIG.13;

FIG. 15 is a cross-sectional view of the filter element depicted inFIGS. 13 and 14, the cross section being taken along the line 15—15 ofFIG. 13;

FIG. 15A is an enlarged, fragmented cross-sectional view of a portion ofthe filter element depicted in FIG. 15;

FIG. 16 is a perspective view of an alternative embodiment of apre-formed insert that may be utilized within the filter elementdepicted in FIGS. 13-15;

FIG. 17 is an end view of the pre-formed insert depicted in FIG. 16;

FIG. 18 is a cross-sectional view of the pre-formed insert depicted inFIGS. 16 and 17, the cross section being taken along the line 18—18 ofFIG. 17;

FIG. 19 is an enlarged, cross-sectional view of a portion of thepre-formed insert shown in FIG. 18;

FIG. 20 is an enlarged, cross-sectional view of another portion of thepre-formed insert depicted in FIG. 18;

FIG. 21 is a cross-sectional view of another embodiment of a filterelement constructed according to principles of this disclosure, andutilizing the pre-formed insert of FIGS. 16-20;

FIG. 22 is a schematic, cross-sectional view of one embodiment of amolding technique for constructing filter elements according to thisdisclosure; and

FIG. 23 is a schematic, cross-sectional view of one embodiment of amolding technique for constructing filter elements according to thisdisclosure.

DETAILED DESCRIPTION

I. A Typical Application—Engine Crankcase Breather Filter

Pressure-charged diesel engines often generate “blow-by” gases, i.e., aflow of air-fuel mixture leaking past pistons from the combustionchambers. Such “blow-by gases” generally comprise a gas phase, forexample air or combustion off gases, carrying therein: (a) hydrophobicfluid (e.g., oil including fuel aerosol) principally comprising 0.1-5.0micron droplets (principally, by number); and, (b) carbon contaminantfrom combustion, typically comprising carbon particles, a majority ofwhich are about 0.1-10 microns in size. Such “blow-by gases” aregenerally directed outwardly from the engine block, through a blow-byvent.

Herein when the term “hydrophobic” fluids is used in reference to theentrained liquid aerosol in gas flow, reference is meant to nonaqueousfluids, especially oils. Generally such materials are immiscible inwater. Herein the term “gas” or variants thereof, used in connectionwith the carrier fluid, refers to air, combustion off gases, and othercarrier gases for the aerosol.

The gases may carry substantial amounts of other components. Suchcomponents may include, for example, copper, lead, silicone, aluminum,iron, chromium, sodium, molybdenum, tin, and other heavy metals.

Engines operating in such systems as trucks, farm machinery, boats,buses, and other systems generally comprising diesel engines, may havesignificant gas flows contaminated as described above. For example, flowrates and volumes on the order of 2-50 cubic feet per minute (cfm),typically 5 to 10 cfm, are fairly common.

FIG. 1 illustrates a schematic indicating a typical system 28 in which acoalescer/separator arrangement according to the present invention wouldbe utilized. Referring to FIG. 1, block 30 represents a turbochargeddiesel engine. Air is taken to the engine 30 through an air filter 32.Air filter or cleaner 32 cleans the air taken in from the atmosphere. Aturbo 34 draws the clean air from the air filter 32 and pushes it intoengine 30. While in engine 30, the air undergoes compression andcombustion by engaging with pistons and fuel. During the combustionprocess, the engine 30 gives off blow-by gases. A filter arrangement 36is in gas flow communication with engine 30 and cleans the blow-bygases. From filter arrangement 36, the air is directed through channel38 and through a pressure valve 40. From there, the air is again pulledthrough by the turbo 34 and into the engine 30. Regulator valve orpressure valve 40 regulates the amount of pressure in the enginecrankcase 30. Pressure valve 40 opens more and more, as the pressure inthe engine crankcase increases, in order to try to decrease the pressureto an optimal level. The pressure valve 40 closes to a smaller amountwhen it is desirable to increase the pressure within the engine. A checkvalve 42 is provided, such that when the pressure exceeds a certainamount in the engine crankcase 30, the check valve 42 opens to theatmosphere, to prevent engine damage.

According to this disclosure, the filter arrangement 36 for separating ahydrophobic liquid phase from a gaseous stream (sometimes referred toherein as a coalescer/separator arrangement) is provided. In operation,a contaminated gas flow is directed into the coalescer/separatorarrangement 36. Within the arrangement 36, the fine oil phase or aerosolphase (i.e., hydrophobic phase) coalesces. The arrangement 36 isconstructed so that as the hydrophobic phase coalesces into droplets, itwill drain as a liquid such that it can readily be collected and removedfrom the system. With preferred arrangements as described hereinbelow,the coalescer or coalescer/separator, especially with the oil phase inpart loaded thereon, operates as a prefilter for carbon contaminantcarried in the gas stream. Indeed, in preferred systems, as the oil isdrained from the system, it will provide some self-cleaning of thecoalescer because the oil will carry therein a portion of the trappedcarbon contaminant.

II. Multi-Stage Oil Aerosol Separator Embodiment, FIGS. 2-9

Referring to FIG. 2, an embodiment of a crankcase gas filter or filterarrangement 36 is depicted at reference numeral 50. The preferred filterarrangement 50 depicted includes a housing 52. The preferred depictedhousing 52 has a two-piece construction. More specifically, housing 52comprises a body assembly 54 and a removable cover member 56. The bodyassembly 54 includes body 55 and lid 57.

Referring to FIGS. 2 and 4, the preferred housing 52 depicted includesthe following 3 ports: gas flow inlet port 58; gas flow outlet port 60;and liquid flow outlet port or liquid drain 62.

In general, the filter arrangement 50 may be generally referenced hereinas a “multi-stage” arrangement because it includes both: (a) a coalescerfilter, to remove a liquid phase from a liquid entrained gas stream;and, (b) at least a single but could include multiple, downstream orsecond stage filters, for further purification of the air stream. InFIG. 4, a cross-sectional view of the filter arrangement 50 includingboth the housing 52 and its internal components is depicted. In general,the filter arrangement 50 includes a first stage coalescer filter 64,and a second stage tubular construction of filter media 66.

In use, an air or gas stream to be modified is directed through theinlet port 58, and through the first stage coalescer filter 64. At leasta portion of the liquid phase is coalesced and removed from the gaseousstream by the first stage coalescer filter 64. The liquid that iscoalesced within the first stage coalescer filter 64 drains by gravity,and in the particular embodiment shown exits the housing 52 through theliquid flow outlet port 62. The gas phase is directed through the secondstage media construction 66. The media construction 66 removes at leasta portion of particulates from the gas stream, and the cleaned gasstream is then directed outwardly from the housing 52 through the gasflow outlet 60.

As can be seen in FIG. 5, preferably the first stage coalescer filter 64and second stage tubular construction of media 66 are a single, unitaryconstruction forming a filter arrangement or element 70. In thepreferred embodiment illustrated, the filter element 70 is removable andreplaceable from the housing 52. By “unitary” in this context it ismeant that the first stage coalescer filter 64 and the second stagetubular construction of media 66 cannot be separated from one anotherwithout destroying a portion of the assembled element 70. In preferredembodiments, end caps 202, 254 form part of the unitary construction.

In reference again to FIG. 4, for the housing 52 depicted, there is aninlet tube construction 72, a regulator valve housing 74, a canisterportion 76, and a outlet tube construction 78. In the embodiment shown,each of the inlet tube construction 72, regulator valve housing 74,canister portion 76, and outlet tube construction 78 form a portion ofthe body 55. Together with the lid 57, the body 55 and lid 57 are partof the body assembly 54.

In the one shown, the inlet tube construction 72 is a cylindrical member80 that defines the gas flow inlet port 58. In preferred assemblies, theinlet tube construction 78 is in gas flow communication with thecrankcase of engine 30, in order to treat blow-by gases emitted from thecrankcase.

The regulator valve housing 74 depicted is immediately downstream of theinlet tube construction 72. The regulator valve housing 74 includes anouter surrounding wall 82 defining an open interior 84, where the gas tobe treated is allowed to flow and collect before passing into the filterelement 70. The regulator valve housing 74 also includes an internalwall 86 forming a neck 88. In the one illustrated, the regulator valvehousing 74 also includes a shelf 90 for holding and supporting the lid57 thereon. The neck 88 holds and supports a regulator valve assembly 92(FIG. 4) between the canister portion 76 and the lid 57.

In reference to FIG. 4, the valve assembly 92 is constructed andarranged to regulate the gas flow from the crankcase of the engine 30and through the filter element 70. While a variety of valveconstructions are contemplated herein, the particular valve assembly 92depicted includes diaphragm construction 94 and a biasing mechanism,such as spring 96. In FIG. 4, note that the diaphragm construction 94 isgenerally circular with an outermost rim 98 that is held by and restsupon shelf 90. The diaphragm construction 94 also includes a groove 100having a generally U-shaped cross-section and being generally circular,in plan view. The groove 100 is inboard of the rim 98. The groove 100helps to keep the diaphragm construction 94 properly oriented andcentered upon the neck 88. Secured to the diaphragm construction 94 is acentering projection 102. The centering projection 102 is sized toextend into the interior portion 104 of the neck 88. In the one shown,the centering projection 102 is secured to the diaphragm construction 94in a region inboard of the groove 100. The centering projection 102,together with the groove 100, helps to keep the diaphragm construction94 properly oriented over the neck 88.

Still in reference to FIG. 4, in the particular valve assembly 92 shown,the spring 96 rests around the outside wall 86 of the neck 88. Thespring 96 applies a force to the diaphragm construction 94 to pull thediaphragm construction 94 in a direction toward the neck 88 and towardthe filter element 70. Note that there is a gap 106 between thediaphragm construction 94 and the neck 88. The gap 106 allows for gasflow from the interior 84 of the regulator valve housing 74 and into theinterior portion 104 of the neck 88.

In operation, the valve assembly 92 generally operates to limit the rateof gas flow from the engine crankcase 30 to the filter element 70. Thespring 96 pulls the diaphragm construction 94 toward the neck 88 againstthe pressure exerted by the gas flow inwardly from the gas flow inlet58. The diaphragm construction 94 is constructed of a flexible material,such as rubber. As such, a diaphragm construction 94 is allowed to flexin a direction away from the neck 88 and toward the lid 57 in the volume108 defined between the lid 57 and the shelf 90 of the regulator valvehousing 74.

In reference now to FIG. 6, the canister portion 76 of the body 55includes an outer surrounding wall 110, that is generally tubular inconstruction to define an open interior 112 for receipt of the filterelement 70. In the one depicted, the wall 110 generally is cylindricalto define a circular cross-section. The canister 76 includes an end wall114 that helps to hold and contain the filter element 70 inside of thecanister 76. The end wall 114 includes a projection 116 extending from aflat, planar portion 118. When the filter element 70 is operablyassembled within the housing 52, the projection 116 will act as asecondary, or supplemental sealing mechanism to create a secondary seal120 (FIG. 4) between the end wall 114 of the body 55 and the element 70.It should be appreciated that the primary sealing function is in aradial sealing system between the filter element 70 and the housing 52,which is described in further detail below. The secondary seal 120 helpsto prevent unintended amounts of oil seepage from passing along the endwall 114 between the filter element 70 and the housing 52.

Still in reference to FIG. 6, note that the body 55 includes a firsttubular region 122 having a first greatest outer dimension and a secondtubular region 124 having a second greatest outer dimension. In theparticular example illustrated, the greatest outer dimensions of thetubular region 122 and tubular region 124 are diameters. The diameter ofthe tubular region 122 is greater than the diameter of the tubularregion 124, to create a stepped region 126 therebetween. The tubularregion 124 defines an inner, annular sealing surface 128. As will bedescribed further below, the sealing surface creates a surface of whichit can accept pressure of a seal member to create a radial sealtherebetween. The tubular region 122 is spaced from the filter element70, when the filter element 70 is operably assembled therein, to createa gas flow volume 130 therebetween.

As can be seen in FIG. 2, the body assembly 54 and the cover member 56are joined to one another along a seam 132 by a latch arrangement 134.The latch arrangement 134 includes a plurality of latches 136 that areused to securely hold the cover member 56 and body assembly 54 togetheralong the seam 132. The latches 136 allow the cover member 56 to beselectively removed from the body assembly 54 in order to accessinternal components, such as filter element 70 during servicing. Therecan be a number of latches, and in the particular embodimentillustrated, there are three latches 136. As can be seen in FIGS. 2, 4,and 6, the body 55 includes a latch mount 138 thereon for each of thelatches 136. In FIG. 2, it can be seen that the cover member 56 includesappropriate latch receiving structure, such as a slot 140, for receivinga hook portion 142 of each of the latches 136.

The body 55 has an open end 144 (FIG. 6) that is opposite of the endwall 114, in the illustrated embodiment. The open end 144 iscircumscribed by a rim 146 that is for communicating with a receivingslot 148 (FIG. 7) in the cover member 56.

Turning now to the cover member 56 illustrated in FIG. 7, note that thecover member 56 has a bowl or funnel-shaped end second 150. Thecombination of bowl 150 and drain 62 comprises a liquid collectionarrangement 152. In use, as liquid coalesces within the housing 52, itwill drain downwardly toward the bowl 150 and will be funneled to thedrain 62. Typically, appropriate drain lines will be secured to thedrain 62 to direct the collected liquid as desired, for example, to anoil sump.

In reference to FIG. 7, still further detail of the illustrated covermember 56 is shown. In the particular embodiment illustrated, in thecover member 56 includes and outer surrounding wall 154 and an innerwall 156 spaced from the outer wall 154. The outer wall 154 and theinner wall 156 together define the slot 148. The slot 148 functions as avolume 158 for receipt of the body assembly 54, in particular, the rim146. The outer surrounding wall 154 also includes the latch receivingstructure 140.

The volume 158 also provides a seat 160 for holding and containing agasket member such as O-ring 162 (FIG. 4). In the construction shown,the O-ring 162 is between the rim 146 and the seat 160. The latcharrangement 154 provides axial forces to squeeze the cover member 56 andbody assembly 54 together. This provides a force of the rim 146 on theO-ring 162 to create a seal 164 (FIG. 4) between the cover member 56 andbody assembly 54. This seal 164 prevents unintended amounts of gas flowto flow between the body assembly 54 and the cover member 56. Rather,the seal 164 forces the gas flow to exit through the gas flow outlet 60.

In reference again to FIG. 7, the inner wall 156 provides an annular,sealing surface 166. The annular sealing surface 166 provides astructure against which a sealing portion of the filter element 70 isoriented to create a radial seal therewith. This is described in furtherdetail below.

The cover member 56 also includes an end wall 168 that is generallynormal to the inner wall 156. The end wall 168 acts as a stop 170 fororientation of the filter element 70. In other words, the stop 170prevents the filter element 70 from moving axially within the housing52. Extending from the end wall 168 is a projection 172. When filterelement 70 is operably installed within housing 52, the projection 172will be pressed against a sealing portion of the filter element 70 tocreate a secondary seal 174 (FIG. 4) with the filter element 70. Thesecondary seal 174 will help to prevent unintended amounts of oilseepage from traveling from within the filter element 70 to the volume130 outside of the filter element 70. Again, the primary sealingfunction is accomplished by a radial sealing system, to be describedfurther below.

Extending from the end wall 168 is a sloped wall 176 that terminates inthe liquid flow outlet 62. The sloped wall 176 forms the funnel shapedsection or bowl 150.

Note that the liquid flow outlet 62 includes a threaded section 178.Threaded section 178 can be a brass insert, and is convenient forconnecting fittings to lead to an oil sump, for example.

Herein, the term “gas flow direction arrangement” or variants thereofwill sometimes be used to refer to the portions of arrangements thatdirect gas flow. For filter arrangement 50, FIG. 4, this would includethe gas flow inlet 58, the inlet tube construction 72, the various wallsof the housing 52 (including the walls 82, 86, 110, and 154) and theoutlet tube construction 78, including the gas flow outlet 60. The gasflow direction arrangement generally operates to ensure proper gas flow,through the filter element 70 in proper order.

Attention is now directed to FIGS. 4 and 5. The filter element 70 isshown in FIG. 4 operably assembled within the housing 52. By the term“operably assembled” and variants thereof, it is meant that the filterelement 70 is oriented within the housing 52 such that the seals are inplace and gas flow is permitted to flow properly from the inlet 58,through the filter element 70, and out through the outlet 60.

It can be seen in FIGS. 4 and 5 that the filter element 70 includes boththe first stage coalescer filter 64 and the second stage tubularconstruction media of 66 in a single construction. When the filterelement 70 is handled, for example during servicing, both the firststage coalescer filter 64 and the second stage tubular construction ofmedia 66 are handled together. In general, the tubular construction ofmedia 66 includes a media pack 190 arranged in a closed, tubular form todefine an open filter interior 192. In preferred constructions, themedia pack 190 will be configured to have a generally cylindrical shape,defining a circular cross section.

In certain preferred arrangements, the media pack 190 includes pleatedmedia 194 defining a plurality of pleats through which gas to be treatedflows. The pleated media 194 acts as a polishing filter to remove atleast some particulates and debris from the gas stream, before exitingthe housing 52 through the gas flow outlet 60.

The pleated media 194 has a first end 196 and an opposite, second end198. The length of the individual pleats of the pleated media 194extends between the first end 196 and second end 198. In the filterelement 70 shown, at the first end 196 is a first end cap arrangement200. In the particular embodiment shown in FIG. 5, the end caparrangement 200 includes an end cap 202 and the first stage coalescerfilter 64. In preferred constructions, the end cap arrangement 200 is asingle, unitary structure.

In preferred embodiments, the end cap 202 includes a ring 204 of amolded, polymeric material. The ring 204 defines a center aperture 206that, in the preferred embodiment illustrated, is centered in the ring204. By “centered”, it is meant that the aperture 206 has a center ofsymmetry that is the same as the center of symmetry of the ring 204. Inother words, the center 206 is preferably not eccentrically disposedwithin the ring 204.

In preferred arrangements, the center aperture 206 will be circular andhave a diameter that is not greater than about 50 percent of thediameter of the ring 204. In some arrangements, the diameter of theaperture 206 will be less than 40 percent of the diameter of the ring204.

The ring 204 also includes an outer, annular surface 208. When filterelement 70 is operably assembled within housing 52, the outer annularsealing surface 208 functions as a sealing portion 210. In preferredarrangements, the sealing portion 210 includes a stepped construction212.

In particular, the stepped construction 212 helps with the insertion andformation of a radial seal 214 (FIG. 4) between the end-cap arrangement200 and the sealing surface 128 of the housing 52. In FIG. 5, thestepped construction 212 includes a first region of largest diameter216, adjacent to a second region 218 of a diameter smaller than thefirst region 216, adjacent to a third region 220 of a diameter smallerthan that of the second region 218. This stepped construction 212 ofdecreasing diameters, results in a construction that helps with theinsertion of the filter element 70 in the body 55.

The sealing portion 210 of the end cap 202 is preferably made from acompressible material, such that there is radial compression of thesealing portion 210 against the sealing surface 128, when the element isoperably installed in the housing 52. Example, usable materials for thesealing portion 210, and preferably the entire end cap 202, aredescribed below. In general, preferred end caps 202 will comprise asoft, polyurethane foam having an as-molded density of typically, lessthan 22 lbs per cubic foot, for example about 14-22 lbs. per cubic foot.

Still in reference to FIG. 5, the end cap arrangement 200 also includesa frame construction 222 oriented in the center aperture 206 of the ring204. The frame construction 222 holds, contains, and encapsulates aregion of fibrous media 224. In the construction shown, the fibrousmedia 224 is used as the first stage coalescer filter 64. In certainpreferred arrangements, the fibrous media 224 comprises at least onelayer, and typically, a plurality of layers 226 of nonwoven, nonpleated,non open tubular, coalescing media. In the embodiment shown in FIG. 5,there are two layers 226, 228 of fibrous media 224. Certain usable,example materials for the fibrous media 224 are described further below.

Still in reference to FIG. 5, in the frame construction 220 depicted,the frame construction 222 is a multi-piece, in particular, a two-piececonstruction including a first frame piece 230 and a second frame piece232. The first frame piece 230 includes a support grid 234 in coveringrelation to the upstream face 236 of the fibrous media 224. The supportgrid 234 is a porous, mesh that permits gas flow to flow therethroughand across the fibrous media 224. The support grid 234 providesstructural support to the fibrous media 224.

Similarly, the second frame piece 232 includes a porous support grid 238in covering relation to the downstream face 240 of the fibrous media224. The support grid 238 also provides structural support for thefibrous media 224, while permitting gas flow to penetrate therethroughand into the open filter interior 192.

In the arrangement shown, the first frame piece 230 and the second framepiece 232 are arranged adjacent to each other to form a retaining pocket242 between the support grid 234 and support grid 238 that holds orencapsulates the fibrous media 224. In certain arrangements, the firstframe piece 230 and the second frame piece 232 fit together, such as bysnap engagement.

As can be seen in FIG. 5, in the embodiment depicted, the frameconstruction 222 is molded or embedded within the polymeric end cap 202,along the inner annular region 244 of the ring 204.

The particular filter element 70 depicted further includes an innersupport liner 246 and an outer support liner 248. Each of the innerliner 246 and outer liner 248 extends between the first end 196 andsecond end 198 of the media pack 190. The inner liner 246 and outerliner 248 help to support the pleated media 194. The liners 246 and 248,in typical arrangements, are constructed of a plastic, porous structurethat permits gas flow therethrough. The outer liner 248 circumscribesthe pleated media 194 and the region of fibrous media 224.

In the particular embodiment illustrated in FIG. 5, the inner liner 246is an integral, unitary part of the second frame piece 232. That is, theinner liner 246 and the second frame piece 232 are a single member. Theinner liner 246 also forms a drain surface 250 for allowing the drippageand flow of coalesced liquid from the first stage coalescer filter 64down to the bowl 150.

The filter element 70 also includes an end cap 254 at the second end 198of the media pack 190. The end cap 254 preferably is constructed of amolded, polymeric material, such that the pleated media 194 is potted orembedded therewithin. Similarly, the inner liner 246 and the outer liner248, in certain preferred embodiments, extend between and are embeddedwithin the molded, polymeric material of the first end cap 202 andsecond end cap 254. The second end cap 254 includes an outer annularsurface 256 that forms a sealing portion 258. Preferably, the sealingportion 258 is compressible, such that it is squeezed against thesealing surface 166 of the cover member 56 when the filter element 70 isoperably installed within the housing 52. The end cap 254 has anaperture 255 that is preferably aligned with the liquid flow outlet 62to allow coalesced liquid to drain from the first stage coalescer filter64, through the aperture 255, and exit through the outlet 62.

Attention is directed to FIG. 4. When the filter element 70 is operablyinstalled within the housing 52, the sealing portion 258 is compressedbetween and against the sealing surface 166 and the outer support liner248 to form a radial seal 260 therebetween. As can be also seen in FIG.4, the sealing portion 210 of the first end cap 202 is compressedbetween and against the sealing surface 128 and the outer support liner248 to form radial seal 214 therebetween. The radial seals 214, 260provide for the primary sealing system within the filter arrangement 50.The radial seals 214, 260 prevent unintended amounts of gas flow tobypass either one or both of the first stage coalescer filter 64 andsecond stage polishing filter 66.

Attention is again directed to FIG. 5. The sealing portion 258 of theend cap 254 also preferably includes a stepped construction 262. Thestepped construction 262 is analogous to the stepped construction 212 ofend cap 202. In the particular embodiment illustrated, there are threesteps of decreasing diameter, including step 264, step 266, and step268. Again, the stepped construction 262 helps in insertion of thefilter element 70 in the housing 52 and the formation of radial seal260.

The end cap 254 preferably comprises a molded, polymeric material, suchas molded polyurethane foam having an as-molded density of typicallyless than 22 lbs per cubic foot, for example, about 14-22 lbs. per cubicfoot. One example material is described further below.

Note that when the end caps 202 and 254 are molded in place, the endcaps 202, 254; the first and second plastic extensions 246, 248; thepleated media 194; and the non-pleated, non-woven fibrous media 24 aresecured together in the form of unitary, cylindrical filter element 70.

An alternative embodiment of filter element 70 is illustrated in FIG. 8at reference numeral 270. Element 270 is analogous to the element 70 ofFIG. 5, in that it includes end cap 272, end cap 274, a region offibrous media 276, pleated media 278, and an outer liner 280. End cap272 includes a central gas stream inlet aperture 272 a. The element 270further includes an inner support liner 282 potted within, and extendingbetween the end caps 272, 274. In this embodiment, there is furtherincluded a flow construction 284 to aid in draining liquid that has beencoalesced by the fibrous media 276.

In the embodiment illustrated in FIG. 8, the flow construction 284includes a tube 286. In typical arrangements, the tube 286 extends fromthe downstream flow face 288 of the coalescer media 276 to the aperture290 of the end cap 274. The length of the tube 286 can vary betweenabout 33%-95% of the total length of the pleated media 278. In manycases, the tube 286 with have a length of at least 25% of the pleatedmedia 278, and usually less than 100% of the length of the pleated media278. In preferred embodiments, the tube 286 will have at least a section287 that is constructed of a generally gas impermeable material, suchthat gas flow is required to exit from the downstream flow face 288,through the tube interior 292, past the end tip 294 of the tube 286, andthen up into the volume 296 before flowing through the pleated media278. The volume 296 is the region between the inner liner 282 and thetube 286. In the particular embodiment depicted, the entire tube 286includes the imperforate section 287. In other embodiments, there may beportions of the tube 286 that are perforated, or gas permeable.

In the embodiment depicted, the tube 286 is part of a frame construction298 that is used to trap, encapsulate, or hold the fibrous media 276.Typically, the frame construction 298 will be molded within the end cap272.

The tube 286 will aid in the drainage of coalesced liquid (typicallyoil). In operation, the coalesced liquid will drain by gravity along theinside wall 300 of the tube 286, and then drip into the bowl 150, andthen exit through the liquid flow outlet 62. The tube 286 will help toprevent coalesced liquid from being drawn into the pleated media 278.

Another alternative embodiment of filter element 70 is illustrated inFIG. 9 at reference numeral 320. Element 320 is analogous to the element70 of FIG. 5, in that it includes end cap 322, end cap 324, a region offibrous media 326, pleated media 328, an outer liner 330, an inner liner332, and a frame construction 334 encapsulating the fibrous media 326.End cap 322 includes a central gas stream inlet aperture 322 a. Thepleated media 328 defines an open tubular interior 333. The element 320further includes an impervious outer wrap 340 circumscribing and incovering relation to the outer liner 330.

In the embodiment depicted, the outer wrap 340 extends between about25-75% of the length of the pleated media 328, typically from the endcap 322 (holding the fibrous media 326) toward the other end cap 324(stopping short of the end cap 324). The outer wrap 340 aids in drainingliquid that has been coalesced by the fibrous media 326, as explainedfurther. In particular, the outer wrap 340 helps to prevent gas flowthrough the region 342 of pleated media 328 that is masked by the wrap340. This encourages gas flow to travel further in the direction towardthe end cap 324, and to the region 344 of media 326 that is not maskedby the wrap 340. This helps in the drainage by gravity of coalescedliquid out of the element 320.

A. Example Operation and Changeout

In operation, the filter arrangement 50 works as follows. Blow-by gasesfrom an engine crankcase are taken in through the gas flow inlet port58. The gases pass into the interior 84 of the regulator valve housing74. The valve assembly 92 permits passage of the gas through the gap 106between the diaphragm construction 94 and the neck 88. The gap 106become larger as the pressure from the engine crankcase increases,causing the diaphragm construction 94 to move against the spring 96 andinto the volume 108 against the lid 57. The gas then flows into theinterior portion 104 of the neck 88. From there, it passes through thefirst stage coalescer filter 64. The first stage coalescer filter 64 issecured within the construction such that the gas is directed throughthe first stage coalescer filter 64 before the gas is directed throughthe pleated media 194.

In particular the gas flow passes through the support grid 234 and intothe layer 228 of fibrous media 224. The gas continues to flow downstreamand through the layer 226, and then through the support grid 238. Thefibrous media 224 separates liquids, with any entrained solids, from therest of the gas stream. The liquid flows out of the media 224 and eitherdrips directly into the bowl 150, or drains along the drain surface 250of the inner liner 246. The collected liquid flows along the sloped wall176 and ultimately through the liquid flow outlet 62. This liquidmaterial often is oil, and may be recycled to the crankcase to bereused.

The gas stream that is not coalesced by the first stage coalescer filter64 continues on to the second stage filter 66. Specifically, the gasflow travels from the open filter interior 192 through the pleated media194. The gas flow is prevented from bypassing this media due to theradial seals 214, 260. The pleated media 194 removes additionalparticles and solids from the gas stream. In the orientation shown inFIG. 4, the pleated media 194 has vertically directed pleats, such thatparticles and any further liquid collects or agglomerates on the pleatsand falls or drain by gravity downwardly toward the bowl 150. Thefiltered gas then exits through the gas flow outlet port 60. From there,the gases may be directed, for example, to the turbo 34 of engine 30.

It should be noted that secondary seals 120, 174 prevent unintendedamounts of collected liquid, such as oil, from seeping between thefilter element 70 and the housing 52.

The filter arrangement 50 is serviced as follows. The cover member 56 isremoved from the body assembly 54 by releasing the latches 136. Thispermits the cover member 56 to be removed from the body assembly 54.When the cover member 56 is removed from the body assembly 54, the seal164 between the body 55 and cover member 56 is released. Further, theradial seal 260 between the filter element 70 and the cover member 56 isreleased. This also provides access to the filter element 70, whichincludes both the first stage coalescer filter 64 and the second stagetubular construction of media 66. The end of the filter element 70adjacent to the end cap 254 is grasped, and the filter element 70 ispulled in an axial direction from the interior 112 of the body 55. Asthe filter element 70 is pulled from the interior 112, the radial seal214 is released. This step removes simultaneously both the first stagecoalescer filter 64 and the second stage polishing filter 66. Thisfilter element 70 may then be disposed of, such as by incineration.

A second, new, replacement filter element 70 is then provided. Thereplacement element 70 also includes the first stage coalescer filter 64and the second stage polishing filter 66 in an analogous construction asthe initial filter element 70. The replacement element 70 including boththe first stage 64 and second stage 66 is inserted through the open end144 of the body 55. The filter element 70 is oriented such that thesealing portion 210 of the end cap 202 is compressed between and againstthe sealing surface 128 and the outer liner 248 to form radial seal 214therebetween. In preferred embodiments, the filter element 70 is alsooriented such that the end cap 202 engages and abuts the end wall 114 ofthe body 55. Next, the cover member 56 is placed over the end of thefilter element 70 and oriented such that the sealing portion 258 of theend cap 254 is compressed between and against the outer liner 248 andthe sealing surface 166 of the cover member 56. This creates the radialseal 260. In preferred arrangements, the filter element 70 is alsooriented such that the end cap 254 axially engages and abuts the stop170 of the cover member 56.

With both radial seals 214 and 260 in place, the cover member 56 is thenlocked to the body assembly 54 by engaging the latches 136. This alsohelps to create the seal 164 between the cover member 56 and body 55.

B. Example Constructions and Systems

The filter arrangement 36 is useful on a 1.5 liter-16 liter engine,50-1200 hp, turbo charged, or super charged, diesel, or natural gas. Inone application, the engine is a 250-400 hp, V-8 engine. The engine hasa piston displacement of at least 3 liters, typically 7-14 liters. Ittypically has 8-16 cfm of blow-by gases generated. Preferred filterarrangements 36 can handle blow-by gases from 1-20 cfm.

In other systems, the filter arrangement 36 is useful on engines withthe following powers: 8 kw-450 kw (11-600 hp); 450-900 kw (600-1200 hp);and greater than 900 kw (>1200 hp). In general, as the power of theengine increases, the second stage pleated media 194 will be increasedin surface area. For example, for engine powers 8 kw-450 kw (11-600 hp),the length of the pleats will be about 4-5 inches; for engine powers450-900 kw (600-1200 hp), the length of the pleats will be about 6-8inches; and for engine powers greater than 900 kw (>1200 hp), there willtypically be more than one filter arrangement 36 utilized. In otherwords, for engine powers greater than 900 kw (>1200 hp), there will beused two filter arrangements 36, each one having a second stage pleatedmedia 194 with a pleat length of 4-7 inches.

It will be understood that a wide variety of specific configurations andapplications are feasible, using techniques described herein. Thefollowing dimensions are typical examples:

Structure At least No greater than (in.) (in.) (in.) Typical outerdiameter of element 70 2 12 4-5 inner diameter of element 70 0.5 101.5-2.5 length of element 70 3 12 4-6 diameter of media 224 0.5 10  2-2.5 thickness of each layer 226, 228 0.05 1 0.1-0.3 diameter ofinlet 58 0.5 3   1-1.5 diameter of gas flow outlet 60 0.5 3   1-1.5diameter of neck 88 0.5 3   1-1.5 height of projection 116 0.01 0.250.05-0.1  diameter of open end 144 3 14 4.5-5.5 diameter of lid 57 3 144.5-5.5 diameter of diaphragm 96 3 14 4.5-5   diameter of inner wall 1563 13 4.5-5   diameter of outer wall 154 3 14   5-5.5 diameter of liquidflow outlet 62 0.05 2 0.1-0.5 height of projection 172 0.01 0.250.05-0.1  length of housing 52 4 15 7-8

C. Example Materials

In this section, certain example materials useful for the embodiment ofFIGS. 2-7 are described. A variety of materials may be used, other thanthose described herein.

The housing 50 can be plastic, such as carbon filled nylon.

The media 224 of the coalescer 64 is generally non-pleated,non-cylindrical, polyester fibrous media having an average fiberdiameter of less than about 18 microns, typically about 12.5 microns anda percent solidity, free state, of no greater than about 1.05%. Themedia 224 has an upstream, and a downstream exposed surface area of atleast 1 in.², no greater than about 7 in.², and typically about 3-4 in.²The material has an average fiber diameter of 1.5 denier (about 12.5micron), and a solidity in a free state of at least 0.85%. It has aweight of, typically, greater than about 3.1 ounces per square yard.Typically, it has a weight less than 3.8 ounces per square yard. Typicalweights are within the range of 3.1-3.8 ounces per square yard (105-129grams per square meter). Typically, the media has a thickness at 0.002psi compression (free thickness) of greater than about 0.32 inches.Typically, the media has a thickness at 0.002 psi compression (freethickness) of less than about 0.42 inches. Typical free thicknesses forthe media are in the range of 0.32-0.42 inches (8.1-10.7 millimeters).The media has a typical permeability of no less than about 370 feet perminute (113 meters per minute).

The end caps 202, 254 may be a polymeric material. In particular, theend caps 202, 254 can be urethane, and more particularly, foamedpolyurethane. One example foamed polyurethane is described in commonlyassigned U.S. Pat. No. 5,669,949 for end cap 3, herein incorporated byreference. The material can be the following polyurethane, processed toan end product (soft urethane foam) having an “as molded” density of14-22 pounds per cubic foot (lbs/ft³) and which exhibits a softness suchthat a 25% deflection requires about a 10 psi pressure. In someembodiments, the “as molded” density varies from the 14-22 lbs/ft³range. The polyurethane comprises a material made with I35453R resin andI305OU isocyanate. The materials should be mixed in a mix ratio of 100parts I35453 resin to 36.2 parts I3050U isocyanate (by weight). Thespecific gravity of the resin is 1.04 (8.7 lbs/gallon) and for theisocyanate it is 1.20 (10 lbs/gallon). The materials are typically mixedwith a high dynamic shear mixer. The component temperatures should be70-95° F. The mold temperatures should be 115-135° F.

The resin material I35453R has the following description:

-   -   (a) Average molecular weight        -   1) Base polyether polyol=500-15,000        -   2) Diols=60-10,000        -   3) Triols=500-15,000    -   (b) Average functionality        -   1) total system=1.5-3.2    -   (c) Hydroxyl number        -   1) total systems=100-300    -   (d) Catalysts        -   1) amine=Air Products 0.1-3.0 PPH        -   2) tin=Witco 0.01-0.5 PPH    -   (e) Surfactants        -   1) total system=0.1-2.0 PPH    -   (f) Water        -   1) total system=0.03-3.0 PPH    -   (g) Pigments/dyes        -   1) total system=1-5% carbon black    -   (h) Blowing agent        -   1) 0.1-6.0% HFC 134A.

The I3050U isocyanate description is as follows:

-   -   (a) NCO content—22.4-23.4 wt %    -   (b) Viscosity, cps at 25° C.=600-800    -   (c) Density=1.21 g/cm³ at 25° C.    -   (d) Initial boiling pt.—190° C. at 5 mm Hg    -   (e) Vapor pressure=0.0002 Hg at 25° C.    -   (f) Appearance—colorless liquid    -   (g) Flash point (Densky-Martins closed cup)=200° C.

The materials I35453R and I3050U are available from BASF Corporation,Wyandotte, Mich. 48192.

The frame construction 222, inner liner 246, outer liner 248, andscreens 234, 238 can be constructed of plastic, such as carbon fillednylon.

The pleated media tubular filter 194 is preferably constructed of anoleo-phobic material. One example is synthetic glass fiber filtermedium, coated and corrugated to enhance performance in ambient air-oilmist conditions. The media 194 has a face velocity of at least 0.1ft/min., no greater than 5 ft/min., and typically about 0.3-0.6 ft./min.The pleat depth is no less than 0.5 in., no greater than 3 in., andtypically about 0.75-2 in. The pleat length is at least 1 in., nogreater than 15 in., and typically 3-6 in. The pleated media 194 has anupstream media surface area of at least 2 ft² and preferably about 3-5ft². There are at least 30 pleats, no greater than about 150 pleats, andtypically about 60-100 pleats. The synthetic glass fiber filter mediamay be coated with a low surface energy material, such as an aliphaticfluorocarbon material, available from 3M of St. Paul, Minn. Prior tocoating and corrugating, the media has a weight of at least 80pounds/3000 sq. ft; no greater than about 88 pounds/3000 sq. ft;typically in a range from about 80-88 pounds/3000 square feet (136.8±6.5grams per square meter). The media has a thickness of 0.027±0.004 inches(0.69±0.10 millimeters); a pore size of about 41-53 microns; a resincontent of about 21-27%; a burst strength, wet off the machine of 13-23psi (124±34 kPa); a burst strength wet after 5 minutes at 300° F. of37±12 psi (255±83 Idea); a burst strength ratio of about 0.30-0.60; anda permeability of 33±6 feet per minute (10.1±1.8 meters per minute).After corrugating and coating, the media has the following properties:corrugation depth of about 0.023-0.027 inches (0.58-0.69 millimeters); awet tensile strength of about 6-10 pounds per inch (3.6±0.91 kilogramsper inch); and a dry burst strength after corrugating of no less than 30psi (207 kPa).

The ratio of the upstream surface area of the coalescer media 224 to theupstream surface area of the pleated media 194 is less than 25%,typically less than 10%, and in some instances, less than 1%. The ratioof the downstream surface area of the coalescer media 224 to theupstream surface area of the pleated media 194 is less than 25%,typically less than 10%, and in some instances, less than 1%.

The housing 52 may be constructed of a molded plastic, such as glassfilled nylon. The diaphragm construction 94 can be constructed of adeflectable material, such as rubber.

III. The Embodiments of FIGS. 10-15

Another alternative embodiment of a coalescer filter and gas cleanerarrangement is depicted in FIGS. 10-12 at 400. The gas cleaner filterarrangement 400 includes a housing 402. The depicted housing 402 has atwo-piece construction. More specifically, housing 402 comprises a bodyassembly 404 and a removable cover member 406. The body assembly 404includes body 405 and lid 407.

Housing 402 includes the following four ports: gas flow inlet port 405;gas flow outlet port 410; port 412; and gas flow bypass outlet port 414.In general, and in reference now to FIG. 12, the gas cleaner filterarrangement 400 includes first stage coalescer filter 416 and secondstage filter media 418. In use in the arrangement shown, the port 412acts as a liquid flow outlet port or liquid drain 412. In thearrangement shown, a liquid entrained gas stream is directed through thegas flow inlet port 408 and then through the first stage coalescerfilter 416. At least a portion of the liquid phase is coalesced andremoved from the gaseous stream by the first stage coalescer filter 416.The liquid that is coalesced within the first stage coalescer filter 416drains and exits the housing 402 through the liquid flow outlet port412. The gas phase is directed from a flow passageway 423 in the firststage coalescer 416 through the second stage filter media 418. The mediaconstruction 418 removes at least a portion of particulates from the gasstream, and the cleaned gas stream is then directed outwardly from thehousing 402 through the gas flow outlet port 410.

As with the embodiment depicted in FIG. 5, the first stage coalescerfilter 416 and the second stage filter media 418 are a single, unitaryconstruction forming a filter arrangement or element 420 (FIGS. 13-15).In preferred designs, the filter element 420 is removable andreplaceable from the housing 402. As with the embodiment of FIG. 5,“unitary” means that the first stage coalescer filter 416 and secondstage media 418 cannot be separated without destroying a portion of theelement 420. In preferred embodiments, the first and second end caps444, 445 are part of the unitary construction.

In reference again to FIGS. 10 and 12, for the body assembly 404depicted, there is an inlet tube construction 422, a valve housing 424,a canister portion 426, and an outlet tube construction 428. In theembodiment shown, each of the inlet tube construction 422, valve housing424, canister portion 426, and outlet tube construction 428 comprise aportion of the body 405. Together with the lid 407, the body 405 and thelid 407 are part of the body assembly 404. The lid 407, in theembodiment depicted, is secured to the body 405 through selectivelyremovable mechanical engagement, such as a bolt arrangement 409. Thebolt arrangement 409 provides selective access to a regulator valveassembly 496.

The filter element 420 is constructed and arranged to be removablymountable within the housing 402. That is, the filter element 420 andthe housing 402 are designed such that the housing 402 can beselectively opened in order to access the filter element 420. The filterelement 420 is designed to be selectively mountable and removable fromwithin an interior 403 of the housing 402. When the filter element 420is oriented as shown in FIG. 12, with all of the seals (to be describedbelow) in place, the filter element 420 is considered to be operablyinstalled within the housing 402.

As mentioned above, the housing 402 is designed to be selectivelyopenable in order to access the filter element 420. In the particularembodiment illustrated, the cover member 406 is secured to the body 405through a latch arrangement 429. The latch arrangement 429 preferablyselectively holds the cover member 406 tightly and securely to andagainst the body 405, when the latch arrangement 429 is in a lockedstate. In the one depicted, the latch arrangement 429 includes at leasttwo latches 433, and in this embodiment, first and second wire latches433.

In reference to FIG. 12, note that the body 405 and cover member 406include a seal arrangement 421. In particular, note that the cover 406includes a pair of opposing flanges 413, 415 defining a receiving slot417 therebetween. The body 405 includes a flange 411 that fits in theslot 417. Preferred embodiments also include an O-ring seal member 419seated within the slot 417.

FIG. 15 depicts the filter element 420 as it would appear in anuninstalled state, that is, when it is not mounted within the housing402. FIG. 13 shows an end view of the filter element 420, while FIG. 14shows an opposite end view of the filter element 420. In general, filterelement 420 includes at least second and first regions 431, 432 offilter media. In the filter element 420 depicted in the drawings, thesecond region of filter media 431 includes a tubular extension 434 thatdefines a tubular open filter interior 436. The second region of media431 also comprises the second stage filter media 418, when the filterelement 420 is installed in the filter arrangement system 400. Inpreferred constructions, the tubular extension of media 434 isconfigured to have a generally cylindrical shape, defining a circularcross-section. In certain preferred arrangements, the second region ofmedia 431 includes fluted or pleated media 438 defining a plurality ofpleats through which gas to be treated is forced to flow through. Thepleated media 438, when installed in the filter arrangement 400,preferably acts as a polishing filter to remove at least someparticulates and debris from the gas stream, and in certain instances, aportion of the entrained liquid, before the gas stream exits the housing402.

The pleated media 438 has a first end 440 and an opposite second end441. The length of the individual pleats, in preferred embodiments,extends between the first end 440 and the second end 441. In the filterelement 420 shown, at the first end 440, is a first end cap arrangement442. In the particular one shown, the first end cap arrangement 442includes an end cap 444 and a rigid, pre-formed insert 446 moldedtherein. In preferred constructions, the first end cap arrangement 442is a single, unitary structure. As will be described further below, thepre-formed insert 446 includes a frame construction 450, which holds thefirst stage coalescer filter 416 in operable assembly.

Still in reference to FIG. 15, at the second end 441 of the pleatedmedia 438, is a second end cap arrangement 443. The second end caparrangement 443 includes at least a second end cap 445.

As mentioned above, the filter element 420 includes at least the secondand first regions of media 431, 432. In preferred arrangements, thesecond region of media 431 includes pleated media 438. The first regionof media 432, in preferred embodiments, is oriented in extension acrossthe tubular extension 434 of the second region of media 431 to be in gasflow communication with the open filter interior 436. By the phrase“oriented in extension across the tubular extension”, it is meant thatthe first region of media 432 does not radially overlap the secondregion of media 431 to itself form a tubular extension; rather, thefirst region of media 432 extends across and covers the end cap aperture445. The first region of media 432 may be itself embedded within the endcap 444 or be oriented adjacent to but spaced from the end cap 444 in adirection toward the end cap 445. The first region of media 432 is notnecessarily contained within a single plane, but in preferredembodiments, the first region of media 432 is a non-tubular,non-cylindrical, generally panel construction 448. By “panelconstruction” it is meant that the first region of media 432 permits gasflow to maintain a generally straight path therethrough. That is, thegas flow is not required to turn a corner as it flows from an upstreamface 452 to a downstream face 454.

In preferred embodiments, and in reference to FIG. 15A, the first regionof media 432 also corresponds to the first stage coalescer filter 416.In preferred embodiments, the first region of media 432 includes fibrousmedia 456. In certain preferred embodiments, the fibrous media 456includes at least one layer, and preferably, a plurality of layers 458of a fibrous bundle of non-woven, non-pleated, non-open tubular,coalescing depth media 459. In the embodiments shown in FIGS. 12 and 15,there are two layers 461, 462 of fibrous depth media 459. Preferredmaterials for the fibrous media 456 are described above in connectionwith media 224 of FIG. 5.

Attention is directed to FIG. 13, where the first end cap 444 is shownin plan view. In preferred embodiments, the end cap 444 includes a ring466 of a molded, polymeric material. The ring 466 defines a centeraperture 468 that, in the preferred embodiment illustrated, is centeredin the ring 466. In other words, the aperture 468 has a center ofsymmetry that is the same as the center of symmetry of the ring 466. Inthe particular embodiment illustrated, the center aperture 468 iscircular. The aperture 468 functions as a gas stream inlet aperture. Theaperture 468 is preferably aligned (either overlapping or coaxial with)the flow passageway 423 of the first stage coalescer filter 416.

The end cap 444 includes an axial portion 470 and an annular or radialportion 472. The aperture 468 provides for gas flow communication withthe open filter interior 436. The axial portion 470 of the end cap 444includes at least one continuous projection 474. In preferredembodiments, the continuous projection 474 helps to form a secondaryseal 476 (FIG. 12) with the housing 402, when the filter element 420 isoperably installed within the housing interior 403. In the particularembodiment illustrated in FIG. 13, the continuous projection 474 forms acircular ring 478.

The radial portion 472 of the end cap 444 forms an annular sealingportion 480. When the filter element 420 is operably assembled withinthe housing 402, the annular sealing portion 480 forms a seal member482. In the preferred embodiment shown in FIG. 13, the seal member 482is along the inner annular surface of the ring 466, to circumscribe theaperture 468.

When the filter element 420 is operably installed within the housing402, the seal member 482 forms a radial seal 484 with the housing 402.In particular, in the arrangement shown in FIG. 12, the body 405 of thehousing 402 includes an internal tube 486. The tube 486 includes a rigidwall 488 that circumscribes and defines a gas flow aperture 490. Whenconstructed as shown in FIG. 12, the wall 488 has a sealing portion 492that is designed to extend through the aperture 468 of the end cap 444and into the open filter interior 436. The wall 488 also has an endportion 494 that may, in certain instances, interact with valve assembly496. The valve assembly 496, its operation, and its interaction with thewall 488 are discussed in further detail below.

In FIG. 12, it can be seen that the radial seal 484 is formed againstthe sealing portion 492 of the tube 486. In preferred embodiments, theradial seal 484 is formed by compression of the material of the firstend cap 444 between and against the sealing portion 492 of the tube 486and the pre-formed insert 446 embedded within the end cap 444. In thiscontext, by “between and against” it is meant that the material of thefirst end cap 444 extends transversely the distance between the sealingportion 492 of the tube 486 and the pre-formed insert 446, and iscompressed in dimension due to the rigidity of portion 492 and insert446.

In reference now to FIG. 15A, the annular sealing portion 480, in theparticular preferred embodiment illustrated, includes a steppedconstruction 498. The stepped construction 498 helps with the insertionand formation of the radial seal 484 between the end cap arrangement 442and the sealing portion 492 of the housing 402. In the preferredembodiment illustrated, the stepped construction 498 includes aplurality of regions of decreasing diameters, extending from the axialportion 470 of end cap 444 to the upstream face 452 of the fibrous media456. In FIG. 15A, the stepped construction 498 includes a first regionof largest diameter 501, adjacent to a second region 502 of a diametersmaller than the first region 501, adjacent to a third region 503 of adiameter smaller than that of the second region 502, adjacent to afourth region 504 smaller than that of the third region 503. Thisstepped construction 498 of decreasing diameters results in sealingportion 480 that helps with the insertion of the filter element 420 intothe housing 402 and the formation of the radial seal 484.

The sealing portion 480 of the end cap 444 is preferably made from acompressible material, such that there is radial compression of thesealing portion 480 against the sealing portion 492 of the tube 486 ofthe housing 402. In general, preferred end caps 444 comprise a soft,polyurethane foam having an as-molded density of about 14-22 pounds percubic foot. One usable material is described above in connection withthe sealing portion 410; another usable material is described furtherbelow.

Referring again to FIG. 12, the filter arrangement 400 preferablyincludes a flow construction arrangement 510 oriented to direct fluid,such as coalesced liquid, from the first region of media 432 toward theliquid flow outlet 412. In general, the flow construction arrangement510 preferably includes a tube 512 formed by a section 513 ofimpervious, continuous, uninterrupted wall 514 surrounding and definingan open, fluid passage 516. In preferred embodiments, the tube 512extends from the downstream face 454 of the first stage coalescer filter416 at least partially in a direction toward the second end cap 445. Inpreferred embodiments, the tube 512 extends a complete distance betweenthe downstream face 454 and the second end cap 445. In the particulararrangement depicted, the tube 512 forms an aperture 520, preferably afluid exit aperture 523, at the end 521 of the wall 514 adjacent to thesecond end cap 445. In this manner, in this particular arrangement,liquid that is coalesced by the first stage coalescer filter 416 isallowed to collect along the interior 517 of the tube 512 and drip bygravity to the liquid flow outlet port 412. Alternate drain arrangementsare also usable. While in the depicted embodiment, the entire wall 514includes the imperforate section 513, in other embodiments, onlyportions of the wall 514 will be imperforate.

In the embodiment of FIG. 8, the flow construction arrangement 284 wasdepicted in the drawing as being generally straight, and unangled. Inthe embodiment of FIGS. 12 and 15, the flow construction arrangement 510is depicted as a conical section 515 having a sloped or tapered wall514. In preferred constructions, the angle of taper on the wall 514 willbe adjusted depending upon the overall length of the element 420. Thatis, in preferred constructions, the size of the aperture 468 generallyremains fixed. As the length of the pleats of the pleated media 438becomes greater, the length of the overall element 420 becomes greater,and the angle or taper of the wall 514 decreases. In many preferredarrangements, the angle of taper, as measured from a longitudinal axis518 (FIG. 15) passing through the symmetrical center of the element 420,is at least 1° extending from end 519 (adjacent to the coalescer filter416) to end 521. In some arrangements, the angle of taper can be 2-15°,and typically less than 45°. The taper or angle on the wall 514 helps todirect the coalesced liquid in the direction of the fluid exit aperture520 and ultimately through the liquid flow outlet port 412.

After passing through the first stage coalescer filter 416, the gasflows through the fluid passageway 516, out through exit aperture 520,and then into a gas flow plenum 522. The gas flow plenum 522 is formedbetween the wall 514 of the tube 512 and the pleated media 438. Thetaper on the wall 514 causes the gas flow plenum 522 to be angledbetween a volume 524 adjacent to the second end cap 445 and a volume 526adjacent to the first end cap 444 that is smaller than volume 524.

In reference now to FIG. 14, the depicted second end cap 445 includes aring 506 defining a center aperture 507. The aperture 507 allows for thepassage of liquid collected by the first stage coalescer filter 416 toexit the filter element 420, in the particular system depicted in FIG.12. The end cap 445 supports a sealing arrangement 508 for forming aseal 509 (FIG. 12) with the housing 402. In the embodiment illustratedin FIG. 12, the particular seal 509 depicted is an axial seal 530 formedbetween the filter element 420 and an inner sealing surface 531 of thecover member 406. In preferred embodiments, the sealing arrangement 508includes a projection 534 extending or projecting in an axial directionfrom a generally flat, planar portion 536 of the second end cap 445. Inmany preferred embodiments, the projection 534 forms a continuous ring538. Preferred constructions include the end cap 445 and the projection534 being a single, unitary, molded construction 540. In preferredembodiments, the end cap construction 540 is made from a polymericmaterial, preferably, a compressible polymeric material such aspolyurethane. In many preferred embodiments, the second end cap 445 ismade from the same material as the first end cap 444. The axial seal 530helps to prevent gas from the inlet port 408 from bypassing the firststage coalescer filter 416 and the second stage construction of filtermedia 418. The axial seal 530 also helps to prevent the seepage ofliquid such as oil from passing to the downstream side of the secondstage filter media 418.

As mentioned above, the first end cap arrangement 442 includespre-formed insert 446. In the embodiment depicted in FIGS. 12 and 15,the pre-formed insert 446 includes frame construction 450 for holdingand encapsulating the fibrous media 456. The frame construction 450 isnow further described. In reference to FIG. 15, the particular frameconstruction 450 depicted is a multi-piece construction 546. In theembodiment shown in FIG. 15A, the multi-piece construction 546 includesat least a first frame piece 550 and a second frame piece 552. The firstframe piece 550 includes a support grid 554 in covering relation to theupstream flow face 452 of the fibrous media 456. Preferably, the supportgrid 554 is a porous, mesh screen 555 (FIG. 13) that permits gas flow,including gas entrained with liquid, to flow therethrough and across thecoalescer media 456. The screen 555 also provides structural support tothe fibrous media 456.

Similarly, the second frame piece 552 includes a support grid 556supporting and in covering relation to the downstream flow face 454 ofthe fibrous media 456. The support grid 556 preferably includes aporous, mesh screen 557 (FIG. 14) and provides structural support forthe fibrous media 456 while permitting gas and coalesced liquid to passtherethrough and into the fluid passageway 516 of the flow constructionarrangement 510.

In the arrangement shown, the first frame piece 550 and the second framepiece 552 are oriented adjacent to each other to form a retaining pocket560 between the screen 555 and the screen 557 to form a housing 562 thatholds or encapsulates the fibrous media 456. In preferred embodiments,the first frame piece 550 and the second frame piece 552 mechanicallyengage, for example, through interlock structure such as a snapengagement 564.

In preferred embodiments, the pre-formed insert 446 forming the frameconstruction 450 is molded or embedded within the polymeric end cap 444along an inner annular region 566 of ring 568. Ring 568, in theembodiment depicted in FIGS. 12 and 15, is integral with and the samepiece as the second frame piece 552. The ring 568 generally comprises asurrounding wall 570 in projection or extending from screen 555 to thefirst axial end 440 of the pleated media 438. As can be seen in FIG.15A, the wall 570 forms a rigid, backstop a to the compression of theend cap material in the sealing portion 480. That is, in preferredconstructions, the radial seal 484 is formed by compression of thesealing portion 480 between and against the backstop 572 and the sealingportion 492 of the wall 488.

As also can be appreciated from reviewing FIGS. 12, 15 and 15A,preferred embodiments include the tube 512 of the flow constructionarrangement 510 as an integral, unitary part of the second frame piece552. As such, in the embodiment illustrated in FIGS. 12 and 15, theparticular second frame piece 552 shown, extends from the end 440, whichforms the backstop 472, along the length of the pleated media 438, tothe end 521 forming the exit aperture 520.

Still in reference to FIGS. 12 and 15, preferred frame constructionsalso include a support ring or frame 574. The support frame 574 helps tocenter the frame construction 450 and to hold the frame construction 450evenly within the open filter interior 436. The support frame 574 can bea variety of arrangements and constructions that provide for structuralrigidity between the tube 512 and an inner perimeter 576 of the pleatedmedia 438. In the particular one depicted in FIGS. 12, 14 and 15, thesupport frame 574 includes a ring construction 578. The ringconstruction 578 depicted mechanically engages the wall 514 adjacent tothe end 521, such as by a snap engagement 582. The ring construction 578depicted includes at least an inner ring 584, which engages the wall514, and an outer ring 586, which may touch or be close to the innerperimeter 576 of the second stage tubular construction of filter media418. The inner ring 584 and outer ring 586 define a plurality of gasflow apertures 588 therebetween, separated by a plurality of spokes orribs 590. The ribs 590 provide for structural support and integrity ofthe ring construction 578. The gas flow apertures 588 allow for thepassage of gas from the first stage coalescer filter 416 to the secondstage filter media 418. That is, after the gas flow has passed throughthe first stage coalescer filter 416 and through the fluid passage 516,it flows through the fluid exit aperture 520, turns a corner (about180°) around the end 521 of the wall 514 and flows through the pluralapertures 588 into the gas flow plenum 522. From there, the gas flowsthrough the tubular extension of media 434.

In certain embodiments, the filter element 420 will also include anouter support 592, such as a liner 594. In preferred arrangements, thesupport 592 will extend between the first and second end caps 444, 445,and help to hold or provide support to the pleated media 438. In someembodiments, the liner 594 includes expanded metal. In manyarrangements, the liner 594, as well as the other parts of the element420, will be non-metallic (at least 98% non-metallic, and preferably100% non-metallic material). In alternate embodiments, instead of aliner 594, the pleated media 438 will include a support band or roving.

As mentioned above, preferred filter arrangements 400 include valveassembly 496. In the preferred embodiment illustrated in FIG. 12, thevalve assembly 496 provides both a regulator valve function and a bypassvalve function. The regulator valve function is first described. Thevalve housing 424 includes an outer surrounding wall 601 defining anopen interior 603, where the gas be treated, which flows from the enginecrank case through the inlet port 408, is allowed to flow and collectbefore passing into the filter element 420. In the illustrated valveassembly 496, there is a diaphragm 602 and a biasing mechanism, such asspring 605. In preferred embodiments, the diaphragm 602 is generallycircular that is held by and rests upon a shelf 608. The shelf 608 issupported between the lid 407 and valve housing 424. Note that in thepreferred embodiment illustrated, there is a gap 610 between thediaphragm 602 and the end portion 494 of the tube 486. The gap 610allows for gas flow from the interior 603 of the valve housing 424 andinto the gas flow aperture 490 of the tube 486. During operation, thespring 605 and the diaphragm 602 regulate flow into the tube 486.

The valve construction 496 also includes a bypass valve function. As themedia in the filter element 420 becomes occluded and restrictionincreases to an unacceptably high level, pressures within the interior603 of the valve housing 424 increase. This applies pressure against thediaphragm 602 and against the spring 604, until the gas is allowed toflow into an interior volume 612 defined by the lid 407. The gas thenflows through the gas flow bypass outlet port 414 (FIG. 10).

Example Operation and Service

In operation, the depicted filter arrangement 400 works as follows.Blow-by gases from an engine crankcase are taken in through the gas flowinlet port 408. The gases pass into the interior 603 of the valvehousing 424. The valve assembly 496 permits passage of the gas and intothe gas flow aperture 490. From there, the gas passes through the firststage coalescer filter 416.

The gas flow passes through the upstream face 452, through the fibrousmedia 456, and out through the downstream face 454. The fibrous media456 separates liquids, with any entrained solids, from the rest of thegas stream. The liquid flows out of the media 456 and, in the depictedembodiment, either drips directly into the liquid flow outlet port 412,or drains along the wall 514 of the flow construction arrangement 510.After passing through the liquid flow outlet port 412, the liquid, whichis often oil, may be directed back into the crankcase for reuse.

The gas stream that is not coalesced by the first stage coalescer filter416 flows through the fluid passage 516, through the exit aperture 520,around the end 521 of the wall 514 (making about a 180° turn) and intothe gas flow plenum 522. From the gas flow plenum 522, the gas flowsthrough the second stage filter media 418, which removes additionalparticles and solids from the gas stream. The gas flow is prevented frombypassing the second stage media 418 due to the radial seal 484 andaxial seals 530, 476. The cleaned gas then flows downstream from thesecond stage filter media 418 out through the gas flow outlet port 410.From there, the gases may be directed to the turbo of the engine.

The filter arrangement 400 is serviced as follows. The cover member 406is removed from the body assembly 404 by disengaging the latches 433.When the cover member 406 is removed from the body assembly 404, theaxial seal 530 is released. The filter element 420 is exposed,projecting out of the body 405. The filter element 420 can then begrasped and pulled from the body 405. This releases the radial seal 484.Removing the filter element 420, of course, removes both the first stagecoalescer filter 416 and the second stage media construction 418. Theentire filter element 420 may be disposed. In many embodiments, thefilter element 420 is constructed of at least 99% non-metallicmaterials, such that the filter element 420 is incineratable.

A second, new filter element 420 may than be installed. The new filterelement 420 is installed within the housing 402 by putting the element420 through the opening exposed by the removed cover member 406. Theaperture 468 of the end cap 444 is oriented around the inlet tube 486,and slid laterally relative to the body 405 until the radial seal 484 isin place. Often, this is also when the projection 474 axially abuts thebody interior 405 and forms an axial seal 476.

The cover 406 is than oriented over the exposed end of the filterelement 420. The latches 433 are engaged, to operably secure the covermember 406 to the body 405. This also axially compresses the cover 406against the element 420, and the axial seal 530 is formed.

IV. The Embodiment of FIGS. 16-21

An alternative embodiment of a preformed insert is shown in FIGS. 16-20,generally at 650. The insert 650 is usable in the filter element 420 inplace of the insert 446. The insert 650 lends itself to convenientmanufacturing techniques and may be preferred, in certain applications.

In general, the insert 650 preferably includes a frame construction 652;a flow construction arrangement 654; and a support ring or frame 656.These parts function analogously to the frame construction 450, flowconstruction arrangement 510, and support frame 574 described inconnection with FIG. 15.

Preferably, the flow construction arrangement 654 includes a tube 660formed by uninterrupted wall 662 surrounding and defining an open, fluidpassage 664. The wall 662 includes a wall section 663 that isimpervious. In the depicted embodiment, the entire wall 662 includesimpervious wall section 663. In other embodiments, the wall 662 mayinclude sections that are permeable to fluid. The wall 662 has aninterior surface 666, which permits coalesced liquid to slide and dripto a liquid outlet port. The wall 662 defines an exit aperture 668, atan end 670 of the tube 660. In many applications, the exit aperture 668allows both gas and liquid to exit therethrough. For example, inpreferred applications, the exit aperture 668 allows the collectedliquid to exit the tube 660 and flow into an appropriate liquid outletport.

As with the embodiment of FIGS. 12 and 15, the wall 662, in preferredarrangements is a conical section 667, being sloped or tapered frominlet end 663 of the wall 662 to exit end 670. That is, in preferredembodiments, when the tube 660 has a circular cross-section, thediameter at the inlet end 663 is larger than the diameter at the outletend 670. In many arrangements, the diameter at the inlet end 663 will beon the order of at least 0.5%, no greater than 25%, and typically 1-10%larger than the diameter at the end 670.

Still in reference to FIGS. 16 and 18, the frame construction 652preferably is provided for holding and encapsulating coalescing media675. The frame construction 652 in this embodiment, is different fromthe frame construction 450 described above. In this particularembodiment, there is a first frame piece 681 and a second frame piece682. The first frame piece has a wall or an outer annular rim 684defining an inner volume 685 (FIG. 19). Axially spanning across one endof the rim 681 and integral with the wall 684 is a support grid 686,preferably in the form of a porous, mesh screen 688. The screen 688provides structural support to the media 675 and permits gas flow toreach the media 675.

The first frame piece 681 also includes an inner rim 690, spacedadjacent to the outer rim 684. The inner rim 690 helps to prevent theflow of polyurethane end cap material from blocking the upstream face692 of the media 675. (Example preferred molding techniques, and thefunction of the rim 690, are described further below.) As can be seen inFIGS. 16 and 17, the inner rim 690 is connected to the outer rim 684with a plurality of ribs 694. The rim 690 is spaced preferably nogreater than 5 millimeters from the outer rim 684 to form end capmaterial (e.g. polyurethane) flow passages 691 therebetween.

The wall or rim 684 preferably defines a recess 696 (FIG. 19) forengaging and receiving a mating detent 698. The detent 698 is part ofthe second frame piece 682, in the particular preferred embodimentillustrated. The detent 698, recess 696 provides for convenient, quickassembly and permits the first and second frame pieces 681, 682 to besnapped together. Of course, many other embodiments of mechanicalengagement between the first and second frame pieces 681, 682 arecontemplated.

The second frame piece 682 preferably includes an annular wall 700surrounding and defining an open volume 702. In the particularembodiment illustrated, the wall 700 has a generally circularcross-section, which may be constant (to form a cylinder) or somewhattapered to conform to the optional taper of the wall 662. The secondframe piece wall 700 includes first and second opposite ends, 704, 706.In the embodiment illustrated, the end 704 generally corresponds to aninlet end 672.

Second frame piece 662 also preferably includes a support grid 708spanning the open volume 702 and integral with the wall 700. Preferably,the grid 708 comprises a screen 710. The screen 710 provides structuralsupport to the coalescing media 675 and preferably engages and holds thedownstream face 712 of the media 675.

The first and second frame pieces 681, 682 form an interior volume orretaining pocket 714 to hold, entrap, and encapsulate the coalescingmedia 675. Preferably, the media 675 is mechanically compressed withinthe pocket 714, such that the grid 686 engages the upstream face 692 andthe grid 708 engages the downstream face 712. As described above, thewall 700 includes a plurality of projections or detents 678 extending orprojecting internally into the volume 702 to engage or snap into therecess 696.

The second frame piece 682 also includes mechanical engagement structureto securably attach to the wall 662 of the tube 660. In particular, thesecond frame piece and the tube 660 also includes mechanical engagementstructure, such as a detent/recess engagement 718. In the particular wayshown in FIG. 19, the wall 700 includes a second plurality ofprojections 720 extending or projecting into the interior volume 702,while the wall 662 has a recess 722 sized to receive the detents orprojections 720. In this manner, the second frame piece 682 easily snapsand interlocks with the tube 660.

Still in reference to FIGS. 16 and 18, preferred frame constructions 652also include support ring or frame 656. The support frame 656 isanalogous to the support frame 574, described above. As such, thesupport frame 656 helps to center the frame construction 652 and hold itevenly within an open filter interior. The support frame 656, in the onedepicted, includes a ring construction 725 having at least an inner ring(728) and an outer ring 730. The inner ring 728 and the outer ring 730are preferably joined by a plurality of spokes or ribs 732. Between theinner rings 728 and outer ring 730, the ring construction 725 defines aplurality of gas flow passageways 734.

Attention is directed to FIG. 20. The ring construction 725 and the tube660 are constructed and arranged to permit convenient manufacturing andassembly. In particular, the ring construction 725 and the tube 660 areconfigured to be secured together, such as by a mechanical engagementarrangement 736. The mechanical engagement arrangement 736 is analogousto those detent/recess arrangements described above. In particular, theinner ring 728 includes a plurality of projections or detents 738extending radially internally of the ring 728. The wall 662 defines arecess 740 to accommodate the projections 738. In this manner, thesupport frame 656 can conveniently and mechanically engage or snap intoplace with structural integrity with the wall 662 of the tube 660.

The preformed insert 660 may be assembled as follows. The tube 660, thering construction 725, and the first and second frame pieces 681, 682are provided, preferably through injection molding techniques. The media675 is provided and preferably includes more than one layer; as shown inFIG. 18, the media 675 is two layers 742, 743 of depth media.

The second frame piece 682 is oriented with respect to the tube 660,such that the opening 707 defined by the wall 700 at the second end 706is placed over an open end 663 of (FIG. 19) of the wall 662 of the tube660. The second frame piece 682 and the tube 660 are mechanicallysecured together through, for example, the mechanical engagement 718 ofthe projection 720 and recess 722. The two layers 742, 743 of media 675are oriented over the screen 710 of the second frame piece 682. Afterthe depth media 675 is placed within the volume or pocket 714, the firstframe piece 681 is secured in position. In particular, the outer rim 684is radially aligned with and inserted through the open end 705 definedby the wall 700 at the first end 704. The first frame piece 681 moveswith respect to the second frame piece 682 along the interior of thewall 700, until the first and second frame pieces 681, 682 are securedtogether in mechanical engagement through the detent 698 and recess 696arrangement.

It should be noted that the first and second frame pieces 681, 682 canbe secured together with the fibrous bundle of media 675 trappedtherebetween before the second frame piece 682 is secured to the tube660.

The ring construction 725 is secured to the tube 660 by sliding the end670 of the tube through the interior of the inner ring 728 and snappingthe pieces together through the mechanical engagement arrangement 736.Of course, the ring 725 and the tube 660 may be secured together at anypoint during the assembly process.

In preferred arrangements, the assembled pre-formed insert 650 may thenbe secured to the remaining portions of the filter element 420 through,for example, molding techniques that are described further below.

In FIG. 21, a filter element 800 is shown in cross-section with theinsert 650 installed therein. It should be understood that, other thanthe insert 650, the filter element 800 is preferably constructedidentically to the filter element 420. As such, the element 800 includesthe first stage coalescer filter media 844, the second stage filtermedia construction 846, a first end cap 856, and an opposite, second endcap 858. Because the element 800 includes the insert construction 650,it includes tube 660, media 675, first frame piece 681, second framepiece 682, ring construction 725, and two layers of depth media 742,743, each as described above.

Also as described above with respect to the filter element 420, the endcap 856 includes an inner, annular sealing portion 864, which forms aseal, preferably a radial seal with portions of an inlet tube. The endcap 858 is also configured analogously to the end cap 445 of FIG. 15,including a projection 870, which forms a seal, preferably an axial sealwith a service cover. The second stage media construction 846 preferablyincludes pleated media 878 extending between the end caps 856, 858. Thepleated media 878 defines an open tubular interior 879.

V. Molding Techniques

Attention is now directed to FIGS. 22 and 23, which depict an examplemolding technique that is usable to manufacture filter elementsdescribed herein. In many preferred arrangements, the insertconstruction (such as preformed insert 446 and preformed insert 650) isassembled in advance, according to techniques described above. Thepreformed insert depicted in FIGS. 22 and 23 is shown generally at 900.The preformed insert 900 includes a frame construction 902 for holdingcoalescer media 904. The preformed insert 900 also includes a tube ortapered wall 906 and a ring construction 908.

Pleated media 910 is provided and formed in a ring or cylinder, aroundthe preformed insert 900. The pleated media 910 with the insert 900 isoriented over a mold 912. Note that the mold 912 includes a platform ormount 914. The frame construction 902 rests upon the mount 914. Moltenmaterial for forming the end cap, such as polyurethane foam, is pouredinto the mold 912 in the volume 916. The molten end cap material 915 isformed in the negative shape of the mold 912. The end cap material 915preferably rises as it cures and is allowed to penetrate the region 691between, for example, the rim 690 and the outer rim 684 in thearrangement depicted in FIG. 17. This permits the end cap material 915to secure the coalescer media 904 to the resulting end cap 918. Thepleats of the pleated media 910 are also then secured to the resultingend cap 918 by being potted or molded into the end cap material 915. Ascan also be seen in FIG. 22, the backstop 920 of the frame construction902 also becomes molded within the end cap 918. If desired, an outerliner 922 is placed around the outer perimeter of the pleats 910 and ismolded with the end cap material 915.

After the end cap 918 is formed, the assembly 924 is inverted and placedinto a mold 926. End cap material 928, such as polyurethane foam, restsin the volume 930. As the end cap material 928 cures, the pleats in thepleated media 910 are molded and fixed in place in the end cap material928 to end up being potted within a resulting end cap 932. Note that thering construction 908 is oriented in a position spaced from the mold 926and with a mold plug 934 adjacent thereto, such that the ringconstruction 908 does not become blocked with end cap material 928.

VI. Principles Related to Size, Efficiency, and Performance; Materials

An arrangement utilizing principles described herein can be configuredin a relatively small package, with efficient operation. For example,the first stage coalescer filter 416/844 is configured to have anupstream surface area of no more than 25%, usually no more than 10% ofthe upstream surface area of the second stage filter media 418/846. Inmany applications, this percentage is much lower, typically 2% or lessand often 1% or less. Typical percentages of the upstream surface areaof the first stage coalescer filter 416/844 to the second stage filtermedia 418/846 are in the range of at least 0.1%, typically 0.2%-1%. Forheavy duty engines (engines having a 12-15 liter piston displacement),the percentage is on the order of less than 0.5%, typically 0.25%. Formedium duty engines (engines having a 6-9 liter piston displacement),the ratio is often less than 0.8%, for example about 0.4%. For lightduty engines (engines having a piston displacement of less than 6liters), the ratio is usually less than 1.5%, for example on the orderof 0.8%.

It is foreseen that systems such as those depicted in the figures willbe configured in relatively small overall packages. For example, overallsizes for the element 420/800 will have an outside diameter of nogreater than 8 inches, and at least 3 inches, with a length of nogreater than 15 inches, and at least 4 inches. For heavy duty engines,the size of the element 420/800 will be about 5.5 inches diameter and 11inches long. For medium duty engines, the element 420/800 will be about5 inches in diameter and 8 inches long. For light duty engines, the sizeof the element 420/800 will be about 4 inches in diameter and 6 incheslong.

When selecting the size for the element 420/800, the amount of filtermedia used in the element 420/800 is adjusted in order to maintain adesirable range of air velocities through the engine. In systemsdescribed herein, it is preferred that the face velocity across thefirst stage filter media 418/844 be maintained at a constant of 250-400feet per minute. Similarly, it is preferable in systems described hereinto maintain the face velocity across the second stage filter media418/846 of no more than 1 foot per minute.

The amount of media for each of the first stage coalescer filter 416/844and second stage filter media 418/846 are selected up to achieveefficient filtering, while limiting the amount of restriction. Insystems described herein, the overall efficiency of the filterarrangement 400 is on the order of at least 80%, and typically 90-95%.By “efficiency”, it is meant the fraction of mass in the gas stream thatis captured or trapped by the first stage coalescer filter 416/844 andsecond stage filter media 418/846. The efficiency of the first stagecoalescer filter 416/844 is usually at least 25%, in some cases nogreater than 70%, typically 30-60%, for example 50%. The second stagefilter media 418/846 preferably has a greater efficiency than the firststage coalescer media 416, on the order of at least 70%, typically80-90%.

Restrictions across the first stage coalescer filter 416/844 are on theorder of 0.5 inch of water at the beginning of the filter life,typically 3-4 inches, and on the order of 5.0 inches of water at the endof the filter life. For the second stage filter media 418/846, therestriction will be at least 0.5 inch of water (typically at thebeginning of the filter life), and up to about 15 inches of water at theend of the life.

Usable Materials

The sealing portions 480, 864, and preferably, the entire end caps 444,856 preferably comprise foamed polyurethane. One example foamedpolyurethane is described above. Another usable foamed polyurethane isas follows: BASF 36361R resin/WUC 3259T isocyanate, with processingconditions of: component temperatures of 75-95° F. for the resin and forthe isocyanate. The mold temperature should be 120-140° F. The demoldtime should be 6 minutes. The compression deflection at 70° F., average10+4/−3 psi; after heat aging 7 days at 158° F., +/−20% change fromoriginal deflection; at −40° F. cold temperature, 100 psi maximumaverage. The compression set, after heat aging 22 hours at 212° F., 15%maximum. The hardness should be 26 Shore A. The tensile strength shouldbe 92 psi target. The elongation should be 120% minimum average. Thetear strength should be 10 lb/in minimum average. The as molded densityshould be less than 30 lbs/ft³, for example, 23-28 lbs/ft³, and can bein the range of 10-24 lbs/ft³.

The housing 402 preferably comprises plastic, such as carbon fillednylon. The preformed inserts 650/446 are preferably injection moldedfrom a synthetic resinous plastic material, such as DELRIN®, availablefrom DuPont.

The media for the coalescer filter 456/884 preferably comprisespolyester, depth media, as characterized above for media 224. The media438/478 for the downstream construction preferably comprises pleatedmedia, as characterized above for media 194.

In general, and in summary, the disclosure concerns an arrangement foruse in separating a hydrophobic liquid aerosol phase, from a gas stream,during filtration of engine crankcase gases; the arrangement comprising:a first stage coalescer filter defining a flow passageway and includinga nonwoven fibrous bundle extending across the flow passageway andhaving a first upstream surface area; and a second stage filtercomprising pleated media positioned downstream from the nonwoven mediaof fibers of the first stage coalescer; the pleated media of the secondstage filter having a second upstream surface area; the first upstreamsurface area being no more than 10% of the second upstream surface area;the arrangement characterized in that: the arrangement includes a firstend cap (202, 272, 322, 444, 856) and a second end cap (254, 274, 324,445, 858); the first end cap (202, 272, 322, 444, 856) including acentral gas stream inlet aperture (206, 272 a, 322 a, 468, 864); thesecond stage filter (66, 278, 328, 418, 846) comprises a tubularconstruction of pleated media (194, 278, 328, 434, 878) extendingbetween the first end cap (202, 272, 322, 444, 856) and the second endcap (254, 274, 324, 445, 858); the tubular construction of media (194,278, 328, 434, 878) defining an open tubular interior (192, 296, 333,436, 879); the central gas stream inlet aperture (206, 272 a, 322 a,468, 864) of the first end cap (202, 272, 322, 444, 856) being in flowcommunication with the open tubular interior (192, 296, 333, 436, 879);the first stage coalescer filter (234, 298, 334, 416, 844) is orientedin extension across the gas stream inlet aperture (206, 272 a, 322 a,468, 864); and the pleated media (194, 278, 328, 434, 878) of the secondstage filter (66, 278, 328, 418, 846), the first end cap (202, 272, 322,444, 856), the second end cap (254, 274, 324, 445, 858), and the firststage coalescer filter (234, 298, 334, 416, 844) are unitary inconstruction.

In some embodiments, the first upstream surface area is no more than 2%of the second upstream surface area. In some embodiments, the firstupstream surface area is no more than 1% of the second upstream surfacearea. In general, the pleated media (278, 434, 878) has a lengthextending between the first end cap (272, 444, 856) and the second endcap (274, 445, 858); and the arrangement further includes: a tube (286,512, 660) within the open tubular interior (192, 296, 436) oriented todirect fluid from the first stage coalescer filter (298, 416, 844); thetube including an imperforate section (287, 513, 663) extending adistance from the first end cap (272, 444, 856) of 33-95% of the lengthof the pleated media (278, 434, 878).

A frame construction (222, 298, 450, 652) is secured to the first endcap; the frame construction including a first frame piece (230, 550,681) and a second frame piece (232, 552, 682) fitted together to definea retaining pocket (242, 560, 714) therebetween; the nonwoven fibrousbundle of the first stage coalescer filter being oriented within theretaining pocket. The first frame piece (681) includes: a cylindricalwall (684) defining an open inner volume (685); and a porous grid (686)integral with the cylindrical wall (684) and extending across the innervolume (685) of the first frame piece; the second frame piece (682)includes: a tubular wall (700) defining an open inner volume (702); anda porous grid (708) integral with the tubular wall (700) extendingacross the open inner volume (702) of the second frame piece; thenonwoven fibrous bundle of the first stage coalescer filter beingpositioned between the first frame piece porous grid (686) and thesecond frame piece porous grid (708).

In some embodiments, the tube (512, 660) includes a conical section(515, 667); the conical section having a tapered wall (514, 662) with anangle of taper of at least 1°; the tapered wall (514, 662) including afirst end (519, 663) adjacent to the first stage coalescer filter and anopposite second end (521, 670) adjacent to the second end cap (445,858); the tapered wall (514, 662) defining a fluid passage (516, 664).

In some embodiments, there is a support ring (725) centering the frameconstruction (652) within the open tubular interior (436); the supportring (725) including: an inner ring (728) secured to the tapered wall(662) adjacent to the second end (670) of the tapered wall (662); anouter ring (730) radially spaced from the inner ring; and a plurality ofspokes (732) between the inner ring and the outer ring; the inner ring,outer ring, and spokes defining a plurality of gas flow passageways(734) to allow for the flow of gas from the fluid passage (664) of thetapered wall (662), around the second end (670) of the tapered wall(662), through the gas flow passageways (734), and into the pleatedmedia (878).

In some embodiments, the second frame piece (552, 682) includes an axialextension forming a ring (568); the first end cap (444, 856) has aninner annular surface (472, 864) comprising a polymeric materialpositioned to form a radial seal (484) with a housing construction, whenthe filter arrangement is operably positioned in a housing construction;the axial extension of the second frame piece (552, 682) forming a ring(568) comprising a backstop (572, 682) to the radial seal (484), whenthe filter arrangement is operably positioned in a housing construction.

In some embodiments, the inner annular surface (472, 864) comprises astepped construction 498 having a plurality of regions (501, 502, 503)of decreasing diameters. The second end cap (445, 858) has an outer,axial projection (474, 870) oriented to form an axial seal (476, 530)with a housing construction, when the filter arrangement is operablypositioned in a housing construction. The second end cap (445, 858)includes a central aperture (255, 290, 507) in fluid communication withthe second end (521, 670) of the tapered wall (514, 662).

In general, there is an insert construction (650) secured to the firstend cap (856); the insert construction (650) including: a coalescerframe construction (652), a flow construction (654), and a support ring(656); the coalescer frame construction (652) and the support ring (656)being secured to the flow construction (654); the coalescer frameconstruction including a first frame piece (681) and a second framepiece (682); the first frame piece (681) including: a cylindrical wall(684) defining an open inner volume (685); a support grid (686) integralwith the cylindrical wall (684) and extending across the inner volume(685) of the first frame piece (681); and an inner rim (690) spacedradially inwardly of and adjacent to the cylindrical wall (684); theinner rim (690) and the cylindrical wall (684) defining material flowpassages (691) therebetween; the second frame piece (682) including: atubular wall (700) defining an open inner volume (702); a support grid(708) integral with the tubular wall (700) extending across the openinner volume (702) of the second frame piece; and an axial extensionforming a ring (568); the nonwoven fibrous bundle of the first stagecoalescer filter being positioned between the first frame piece supportgrid (686) and the second frame piece support grid (708); the first endcap (856) having an inner annular sealing surface (864) comprising apolymeric material; the ring (568) of the second frame piece (682)comprising a backstop (572, 682) to the inner annular sealing surface(864), when the filter arrangement is operably positioned in a housingconstruction; the flow construction (654) includes a tube (660) withinthe open tubular interior (879); the tube (660) including a tapered wall(662) including a first end (663) adjacent to the first stage coalescerfilter (844) and an opposite second end (670) adjacent to the second endcap (858); the tapered wall (662) defining a fluid passage (664)therewithin; the tapered wall (662) having an angle of taper of at least1°; and the support ring (725) centering the frame construction (652)within the open tubular interior (879); the support ring (725)including: an inner ring (728) secured to the tapered wall (662)adjacent to the second end (670) of the tapered wall (662); an outerring (730) radially spaced from the inner ring; a plurality of spokes(732) between the inner ring and the outer ring; the inner ring (728),outer ring (730), and spokes (732) defining a plurality of gas flowpassageways (734) therebetween to allow for the flow of gas from thefluid passage (664) of the tapered wall (662), around the second end(670) of the tapered wall (662), through the gas flow passageways (734),and into the pleated media (878).

In some embodiments, the first frame piece (681) and a second framepiece (682) are secured together by a detent and recess interlock (696,698); the second frame piece (682) and the tapered wall (662) aresecured together by a detent and recess interlock (720, 722); and theinner ring (728) is secured to the tapered wall (662) by a detent andrecess interlock (738, 740).

Preferably, there is a housing (52, 402) defining an interior and havinga gas flow inlet (58, 405), a gas flow outlet (60, 410), and a liquidflow outlet (62, 412); the pleated media (194, 344, 434, 878), the firstend cap (202, 272, 322, 444, 856), the second end cap (254, 274, 324,445, 858), and the first stage coalescer filter (234, 298, 334, 416,844) forming a filter element operably oriented within the housinginterior; the first end cap (444, 856) having an annular surface (210,472, 864) comprising a polymeric material form a radial seal (214, 484)with the housing (52, 402).

Preferably, the arrangement is used as part of a blow-by recoverysystem.

There is also provided a method of treating diesel engine blow-by gases;the method comprising steps of directing blow-by gases from a dieselengine to a coalescer filter; removing at least a portion of a liquidphase from the gases with the coalescer filter as a collected liquid;after said step of removing at least a portion of a liquid phase,directing the gases through a tubular media filter; filtering at least aportion of particulates from the gases with the tubular media filter,and after said step of removing at least a portion of the collectedliquid phase, directing drainage of at least a portion of the collectedliquid from the coalescer filter, along a flow construction arrangementin the interior of the tubular media filter, to an outlet.

In many embodiments, the step of directing drainage includes draining bygravity the collected liquid along a flow construction arrangementincluding an inner tube oriented within the interior of the tubularmedia filter. In many instances, the step of directing the gases throughthe tubular media filter includes directing the gases along the interiorvolume of the inner tube, around an end of the inner tube, and into agas flow plenum between a volume outside of the inner tube and inside ofthe tubular media filter.

There is also provided a method of servicing a filter arrangement; themethod comprising: removing a cover member from a body assembly;installing a filter element into the body assembly; the step ofinstalling the filter element includes simultaneously installing acoalescer filter and a tubular media filter with a liquid flowconstruction arrangement; and securing the cover member to the bodyassembly.

In preferred methods, the step of installing includes forming a radialseal between the filter element and the body assembly. Also, inpreferred methods, the step of installing includes installing acylindrical extension of pleated media with a region of fibrous mediaoriented in a first end cap at one end of the extension of pleatedmedia.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein.

1. An arrangement for use in separating a hydrophobic liquid aerosolphase, from a gas stream, during filtration of engine crankcase gases;the arrangement comprising: a first stage coalescer filter defining aflow passageway and including a nonwoven fibrous bundle extending acrossthe flow passageway and having a first upstream surface area; and asecond stage filter comprising pleated media positioned downstream fromthe nonwoven media of fibers of the first stage coalescer; the pleatedmedia of the second stage filter having a second upstream surface area;the first upstream surface area being no more than 10% of the secondupstream surface area; the arrangement characterized in that: (a) thearrangement includes a first end cap and a second end cap; (i) the firstend cap including a central gas stream inlet aperture; (b) the secondstage filter comprises a tubular construction of pleated media extendingbetween the first end cap and the second end cap; (i) the tubularconstruction of media defining an open tubular interior; (ii) thecentral gas stream inlet aperture of the first end cap being in flowcommunication with the open tubular interior; (c) the first stagecoalescer filter is oriented in extension across the gas stream inletaperture; and (d) the pleated media of the second stage filter, thefirst end cap, the second end cap, and the first stage coalescer filterare unitary in construction.
 2. An arrangement according to claim 1wherein: (a) the first upstream surface area is no more than 2% of thesecond upstream surface area.
 3. An arrangement according to claim 1wherein: (a) the first upstream surface area is no more than 1% of thesecond upstream surface area.
 4. An arrangement according to claim 1wherein: (a) the pleated media has a length extending between the firstend cap and the second end cap; and (b) the arrangement furtherincludes: (i) a tube within the open tubular interior oriented to directfluid from the first stage coalescer filter; (A) the tube including animperforate section extending a distance from the first end cap of33-95% of the length of the pleated media.
 5. An arrangement accordingto claim 4 further including: (a) a frame construction secured to thefirst end cap; the frame construction including a first frame piece anda second frame piece fitted together to define a retaining pockettherebetween; (i) the nonwoven fibrous bundle of the first stagecoalescer filter being oriented within the retaining pocket.
 6. Anarrangement according to claim 5 wherein: (a) the first frame pieceincludes: a cylindrical wall defining an open inner volume; and a porousgrid integral with the cylindrical wall and extending across the innervolume of the first frame piece; (b) the second frame piece includes: atubular wall defining an open inner volume; and a porous grid integralwith the tubular wall extending across the open inner volume of thesecond frame piece; (i) the nonwoven fibrous bundle of the first stagecoalescer filter being positioned between the first frame piece porousgrid and the second frame piece porous grid.
 7. An arrangement accordingto claim 6 wherein: (a) the tube includes a conical section; the conicalsection having a tapered wall with an angle of taper of at least 1°; (i)the tapered wall including a first end adjacent to the first stagecoalescer filter and an opposite second end adjacent to the second endcap; the tapered wall defining a fluid passage.
 8. An arrangementaccording to claim 7 further including: (a) a support ring centering theframe construction within the open tubular interior; the support ringincluding: (i) an inner ring secured to the tapered wall adjacent to thesecond end of the tapered wall; (ii) an outer ring radially spaced fromthe inner ring; and (iii) a plurality of spokes between the inner ringand the outer ring; (A) the inner ring, outer ring, and spokes defininga plurality of gas flow passageways to allow for the flow of gas fromthe fluid passage of the tapered wall, around the second end of thetapered wall, through the gas flow passageways, and into the pleatedmedia.
 9. An arrangement according to claim 6 wherein: (a) the secondframe piece includes an axial extension forming a ring; (b) the firstend cap has an inner annular surface comprising a polymeric materialpositioned to form a radial seal with a housing construction, when thefilter arrangement is operably positioned in a housing construction; (i)the axial extension of the second frame piece forming a ring comprisinga backstop to the radial seal, when the filter arrangement is operablypositioned in a housing construction.
 10. An arrangement according toclaim 9 wherein: (a) the inner annular surface comprises a steppedconstruction having a plurality of regions of decreasing diameters. 11.An arrangement according to claim 1 wherein: (a) the second end cap hasan outer, axial projection oriented to form an axial seal with a housingconstruction, when the filter arrangement is operably positioned in ahousing construction.
 12. An arrangement according to claim 7 wherein:(a) the second end cap includes a central aperture in fluidcommunication with the second end of the tapered wall.
 13. Anarrangement according to claim 1 further including: (a) an insertconstruction secured to the first end cap; the insert constructionincluding: a coalescer frame construction, a flow construction, and asupport ring; the coalescer frame construction and the support ringbeing secured to the flow construction; (i) the coalescer frameconstruction including a first frame piece and a second frame piece; (A)the first frame piece including: a cylindrical wall defining an openinner volume; a support grid integral with the cylindrical wall andextending across the inner volume of the first frame piece; and an innerrim spaced radially inwardly of and adjacent to the cylindrical wall;the inner rim and the cylindrical wall defining material flow passagestherebetween; (B) the second frame piece including: a tubular walldefining an open inner volume; a support grid integral with the tubularwall extending across the open inner volume of the second frame piece;and an axial extension forming a ring; (C) the nonwoven fibrous bundleof the first stage coalescer filter being positioned between the firstframe piece support grid and the second frame piece support grid; (D)the first end cap having an inner annular sealing surface comprising apolymeric material; the ring of the second frame piece comprising abackstop to the inner annular sealing surface, when the filterarrangement is operably positioned in a housing construction; (ii) theflow construction includes a tube within the open tubular interior; (A)the tube including a tapered wall including a first end adjacent to thefirst stage coalescer filter and an opposite second end adjacent to thesecond end cap; the tapered wall defining a fluid passage therewithin;the tapered wall having an angle of taper of at least 1°; and (iii) thesupport ring centering the frame construction within the open tubularinterior; the support ring including: (A) an inner ring secured to thetapered wall adjacent to the second end of the tapered wall; (B) anouter ring radially spaced from the inner ring; (C) a plurality ofspokes between the inner ring and the outer ring; (D) the inner ring,outer ring, and spokes defining a plurality of gas flow passagewaystherebetween to allow for the flow of gas from the fluid passage of thetapered wall, around the second end of the tapered wall, through the gasflow passageways, and into the pleated media.
 14. An arrangementaccording to claim 13 wherein: (a) the first frame piece and a secondframe piece are secured together by a detent and recess interlock; (b)the second frame piece and the tapered wall are secured together by adetent and recess interlock; and (c) the inner ring is secured to thetapered wall by a detent and recess interlock.
 15. An arrangementaccording to claim 1 further including: (a) a housing defining aninterior and having a gas flow inlet, a gas flow outlet, and a liquidflow outlet; (i) the pleated media, the first end cap, the second endcap, and the first stage coalescer filter forming a filter elementoperably oriented within the housing interior; (ii) the first end caphaving an annular surface comprising a polymeric material forming aradial seal with the housing.
 16. A method for separating a hydrophobicliquid aerosol phase, from a gas stream, during filtration of enginecrankcase gases; the method comprising: (a) directing the gas stream ina gas stream inlet aperture in an arrangement; the arrangement includinga first end cap and a second end cap; (i) the first end cap includingthe central gas stream inlet aperture; (b) separating a liquid aerosolphase from the gas stream by directing the gas stream through a firststage coalescer filter oriented in extension across the gas stream inletaperture; and (c) after separating a liquid aerosol phase from the gasstream, directing the gas stream through a second stage filtercomprising a tubular construction of pleated media extending between thefirst end cap and the second end cap; (i) the tubular construction ofmedia defining an open tubular interior; (ii) the central gas streaminlet aperture of the first end cap being in flow communication with theopen tubular interior; and (iii) the pleated media of the second stagefilter, the first end cap, the second end cap, and the first stagecoalescer filter being unitary in construction.
 17. A method accordingto claim 16 wherein: (a) said step of separating a liquid aerosol phasefrom the gas stream by directing the gas stream through a first stagecoalescer filter includes directing the gas stream through a first stagecoalescer filter having an upstream surface area not greater than 10% ofthe upstream surface area of the second stage filter.
 18. A methodaccording to claim 16 wherein: (a) said step of separating a liquidaerosol phase from the gas stream by directing the gas stream through afirst stage coalescer filter includes directing the gas stream through afirst stage coalescer filter having an upstream surface area not greaterthan 2% of the upstream surface area of the second stage filter.
 19. Amethod according to claim 16 further comprising: (a) after said step ofseparating a liquid aerosol phase from the gas stream, draining theliquid aerosol phase through an aperture in one of the first and secondend caps.
 20. A method according to claim 19 wherein: (a) said step ofdraining the liquid aerosol phase includes draining the liquid aerosolphase through an aperture in the second end cap.